Ah, where to begin? I am reviewing the US version of the Asus Zenfone 2 ZE551ML. My particular model is the 4GB/64GB version in red. The US version comes in two varities with the differences being the amount of RAM, the amount of internal storage, and the chipset/CPU. The differences are shown in the specs below. The US version has all the available bands for US carriers, especially for 4G LTE (bands 1, 2, 3, 4, 5, 7, 8, 17, 20).

Many others have written/recorded their own reviews of the ZF2 but none of them are here on Techist. Most of those reviews were also written by what I call "phone snobs" who are used to the top end flagship models of the various manufacturers and therefore seldom dirty themselves with a phone normal people could actually afford to buy without a carrier subsidy. I cannot count myself among them, thankfully. I am a working guy who has chosen to go prepaid and without a contract thus I have to buy my phones outright without any kind of a subsidy.

The phone itself looks stunning. It is sleek despite being large. Obviously if you do not favor large displays then you will disagree on this point. The screen-to-body ratio is 70.1% so you do not end up with a hand full of bezel. I measured the side bezels at .125"/3mm, the top at .5"/12.7mm, and the bottom at .3125"/8mm (.6875"/17.5mm if you count the capacitive buttons). While it is 10.9mm thick that is only for the center of the phone as the back curves/tapers down to .1875"/4.75mm on the edges.

The Zenfone 2 is wholly glass and plastic, but it doesn't feel "plasticy". Overall it feels nice and solid with no creaks when it is gripped in the hand. In fact the back plate has a very tight fit with many complaining about how hard it is to open it up. While it is stiff it is not that bad and I much prefer a very snug fit to one that is loose. You find the volume rocker on the back plate just under the camera much like LG's design; the power button, however, it located in the center of the top of the phone (more on that later). The back plate itself is crafted to resemble machined aluminum and looks stylish rather than cheesy. The texturing of the back cover helps keep it from being a fingerprint magnet. Following the faux metal theme is the chin of the phone; it has a swirl pattern to it that seem to radiate from the center of the chin much like machined metal would. The remainder of the front is completely covered by Gorilla Glass 3 including the bezels.

Beneath the rear cover you find the dual SIM slots, a microSD slot, and the non-removable battery. The battery is another sticking point for some in that it is built into the phone. I don't have much of a problem with it myself as I figure it could be removed and replaced just as an iPhone's battery can be removed and replaced but it would not be as simple as popping it out and dropping in another one in its place.

The screen itself is crisp and clear due to the 1080p resolution. Instead of onscreen buttons Asus opted for capacitive buttons just below the screen. The buttons give the phone the full 5.5" for the screen but add to the overall size of the phone. The capacitive buttons are not backlit which is one of the few cons I have for this phone. The screen's maximum brightness is less than many other phones which can make using it in full sunlight a little difficult, and I have read that the minimum brightness is not dim enough but I don't ever see me using the phone that way.

The 4GB/64GB version of the phone supports Qualcomm Quick Charging 2.0 and comes with a 18W BoostMaster charger (the 2GB/16GB version supports it but does not come with the BoostMaster charger in the box). The only other things included in the box is a microUSB cable and the Asus literature. I did find getting into the box an adventure as the outer cover slides off the box but it a very, very snug fit. I thought I was going to have to cut it open but finally got it open without resorting to violence.

So, how is the phone in real world usage? Darn good, actually. The Zenfone 2 has the knock on/knock off feature which I quickly fell in love with. This feature is why I do not get people complaining about the power button being in the center of the top of the phone. I rarely have to bother with the power button itself in day to day use. The only drawback to it is that you have to be on a home screen to knock off; it does not work from inside an open app.

The phone is very fast, at least to me. I came from an LG Optimus G Pro to the Zenfone 2 so I have a decent baseline to measure from for the actual performance. The ZF2 pulls up apps without any stutter with the 4GB of RAM letting it hold lots of apps at ready instead of killing them off and then relaunching them. To see just how killer this truly is watch this video that runs the ZF2 against an iPhone 6+ (I don't know what language he is speaking but the video stands on his own without the voiceover). I don't really game on phones but my wife likes gaming on my ZF2 due to its large screen and the fact that it has the horsepower to play more demanding games.

The Zenfone 2 comes with ZenUI, Asus' own brand of launcher/user interface. Honestly, ZenUI is pretty good in real world usage. It looks good, runs smooth, you can use different themes, and you can use different icon packs all in the native launcher. My only complaint about ZenUI was that it only displays four icons horizontally, like this:

I found a way to adjust the DPI of the phone so that I could use ZenUI and get five icons. At first this did not work very well as I use SwiftKey and it did not work with the DPI change, but SwiftKey had an update and now it scales with the DPI.

ZenUI also lets you install and use themes as well as icon packs. The number of themes are small so far (around 10-12) but they are growing. You can use any icon pack with ZenUI, however. The screenshots above are of the default theme with a custom wallpaper. Here are a few other themes that I have installed, each with its native icons and wallpaper: Iron theme, Simple Blue theme, ZenBlu theme*, and Fresh Green theme. Other themes include Travel, ZenMaterial*, Polar Bear, China, Afternoon Tea, Bunny Angie, and Lovely Pink. Themes marked with an * denote those made by someone other than ZenUI Design from Asus. All can be found in the Google Play store.

I have found the camera to be quite good. I have read varying other opinions , from it being trash to it being stellar. I am not a photographer and don't snap a lot of shots but I like to be able to do so and not have to worry about whether it will look like crap or not. So far the camera has done well for me.

The battery life has been great so far. I get a full day out of it and still have some juice left when I get home. My phone doubles as my e-reader so it gets plenty of screen on time throughout the day. I also use my phone in the place of my work netbook for entering my time, doing my paperwork, and other such tasks. I use it to pull up webpages for work or whatever else strikes my fancy at the time. I use Bluetooth in the car when I make phone calls or am expecting a call. I can think of one day that I got home and was between 10% and 15% on the battery but I usually have 20-30% or more. The fast charge works as advertised, charging the phone around 60% in about 40 minutes. The phone does get warm when using the BoostMaster charger but I normally plug mine up through my computer when I go to bed.

There are already a huge selection of cases available for the Zenfone 2. I ordered several to see what I liked. I didn't order either of the official Asus covers as they seemed too expensive. Of those I did order I am using Nilkin Crystal clear TPU case so as to show off the beauty of the phone. I like the Amzer TPU case but it is black so it shows the red around the cutouts. I am using a tempered glass screen protector as well. I tried a couple of the window cases but both are knock-offs and the circle of the window is not quite large enough to see the battery ring in the window display. Asus is supposed to be coming out with different backs/battery covers for the phones soon that will be in different colors and textures.

Overall I am very pleased with my Asus Zenfone 2, especially for the price. It is a definite bang for the buck winner. Having bragging rights about owning the first phone with 4GB of RAM is pretty sweet as well. I have gotten many compliments on the looks of the phone and have had several have me write down where they could order one for themselves. So far Asus has been pushing out an OTA every other week and will soon be unlocking the bootloader for development, not to mention that they are working on 5.1 for the phone.

Well, that's my review of sorts. I hope you all like it. If you have any questions post them up and I will get about answering them.

Neat addition to the above. The Zenfone 2 has built-in call recording. If you check out the screenshot I attached you will see the REC button on the right side in the middle. I hadn't played with it but came across a tips and tricks video that mentioned it.

Nice review.
For the price this is probably one of the best phones.
Other great phones around this price would be the OPO and the Alcatel One Touch Idol 3.

If you like having more icons, get the Nova launcher, it's free, it's the best launcher imo, you can make so many changes and it's also faster, try it out if you dare!
I'm not a fan on other skins like LG and Samsung so this phone is not for me plus I'd go crazy with all the bloat ware however for the price, you're getting a lot, a little too much if you really think about it.
Glad you finally found a good phone that you like.

Nice review.
For the price this is probably one of the best phones.
Other great phones around this price would be the OPO and the Alcatel One Touch Idol 3.

If you like having more icons, get the Nova launcher, it's free, it's the best launcher imo, you can make so many changes and it's also faster, try it out if you dare!
I'm not a fan on other skins like LG and Samsung so this phone is not for me plus I'd go crazy with all the bloat ware however for the price, you're getting a lot, a little too much if you really think about it.
Glad you finally found a good phone that you like.

I seriously looked at the Idol 3 but went with the Asus name. This phone definitely shines hardware-wise.

Funny that you suggested Nova Launcher as the Prime version is what I run now. I have used Go Launcher many times before because it has so many themes available but I got tired of them pushing their ads and other products on me. Nova is nice and slick and doesn't lag at all. I haven't bothered with any real themes as I use one of Asus's wallpapers (the red one to match the phone) and an icon pack, 3K MNML White.

Most of the bloatware can be removed without a hassle. Some people have discovered which apps to leave alone as removing them and then updating causes issues. I got rid of what annoyed me and haven't bothered with the rest as I have plenty of space; I did disable them from starting, though.

Asus has since brought out a 128GB version, dubbed Zenfone 2 Delux. Same hardware except for the additional storage, but it has a really snazzy back on it. Well, they have also brought out other variants like the ZF Zoom (more camera-centric), ZF2 Laser (laser auto-focus, in both 5.5" and 5"), ZF Go, ZF 2E... yeah. Anyway, here's the ZF2 Delux: